硼化物陶瓷:烧结致密化、微结构调控与性能提升

Boride Ceramics: Densification, Microstructure Tailoring and Properties Improvement

TiB2、ZrB2、HfB2、B4C及BN为代表的硼化物陶瓷具有优异的物理化学性能,在超高温、超硬以及超疏水等极限条件下有广阔的应用前景,但材料的烧结致密化困难、断裂韧性低等问题制约了它们更为广泛的应用.本文针对无压烧结在材料制备过程中的优势,探讨了影响硼化物陶瓷无压烧结的主要因素,总结了以"除氧"机制为代表的硼化物陶瓷无压烧结技术;针对硼化物陶瓷韧性低的不足,介绍了以"板晶增韧"、"纳米相增强"为代表的硼化物陶瓷微结构调控手段和强韧化措施.最后,文章还对硼化物陶瓷的织构化设计、制备方法与性能提升进行了简要介绍.

Borides,including TiB2,ZrB2,HfB2,B4C and BN,have good physical and chemical properties,which have been proposed for a variety of applications in extreme environments,such as ultra-high temperature,super-hard and super-hydrophobic.However,the engineering applications of these borides are still restricted by their poor sinterability and unsatisfied material properties including low fracture toughness.In regard with the advantages of pressureless sintering in preparation of ceramics,the main factors that affect the pressureless sintering of borides are discussed.The pressureless sintering technology of borides represented by oxygen removing mechanism is summarized.In consideration of the low toughness of borides,the microstructure tailoring methods represented by platelet toughening and nano phase reinforced are emphasized.At last,the methods for preparing textured boride ceramics are also briefly introduced.